Developing Prestressed Concrete Girder Cross-Sections for Longer Spans and New Materials

Precast, prestressed concrete girders are the work-horses of the bridge construction industry. Their initial cost-effectiveness and their low maintenance requirements lead to low life-cycle costs and make them ideal for building short- to medium-span bridges, such as freeway over-crossings. However, spans of such bridges are relentlessly increasing, due to constraints caused by environmental restrictions and urban congestion, and the consequent difficulties in locating columns. The longer spans require deeper girders to sustain the in-service bending moments, but they also pose challenges with respect to lateral stability during handling and transportation. At the present record span (223 ft) the cross-sections in present use (WSDOT WF sections, Florida Bulb tees, PCI bulb tees, etc.) are close to their stability limits. To address these stability concerns, there is a pressing need to consider new cross-section shapes. Criteria for selection will include both in-service bending and shear capacities, and lateral stability during transportation. In addition, the shipping weight of such long girders is also increasing, so there is pressure to design the girder sections to have the greatest strength/weight ratio possible, which implies the use of lightweight concrete and minimization of dimensions wherever possible. However, lightweight concrete typically has a lower elastic modulus, which lowers the buckling load, and the benefits of using it depend on the relative magnitudes of the changes in weight and stiffness. Furthermore, new, high-strength materials such as ultra high performance concrete (UHPC) can contribute to the solution but, because their strengths in different modes (shear, tension, compression) do not appear in the same relative proportions as in existing concretes, the optimization of the girder cross-sections will require careful consideration of all these characteristics.

• Record URL:
  https://abc-utc.fiu.edu/research-projects/uw-research-projects/developing-prestressed-concrete-girder-cross-sections-for-longer-spans-and-new-materials/

Language

• English

Project

• Status: Active
• Funding: $70000
• Sponsor Organizations:

  Accelerated Bridge Construction University Transportation Center (ABC-UTC)

  Florida International University
  10555 W. Flagler Street
  Miami, FL  United States  33174

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Performing Organizations:

  University of Washington, Seattle

  Civil and Environmental Engineering Department
  201 More Hall, Box 352700
  Seattle, WA  United States  98195-2700
• Principal Investigators:

  Wiebe, Richard

  Stanton, John

• Start Date: 20220601
• Expected Completion Date: 0
• Actual Completion Date: 0
• USDOT Program: University Transportation Centers

Subject/Index Terms

• TRT Terms: Bridge design; Cross sections; Girders; Long span bridges; Prestressed concrete
• Subject Areas: Bridges and other structures; Construction; Design; Highways; Materials;

Filing Info

• Accession Number: 01889305
• Record Type: Research project
• Source Agency: Accelerated Bridge Construction University Transportation Center (ABC-UTC)
• Files: UTC, RIP
• Created Date: Jul 30 2023 9:12PM